Researchers: Inadequate vaccination rates fueled recent measles outbreak

In a somewhat frightening illustration of anti-vaccine trends, a new report estimates that among groups affected in the recent measles outbreak, the rates of measles-mumps-rubella immunization might have been as low as 50 percent.

Earlier this month, a report published in JAMA Pediatrics concluded that MMR vaccination rates in many of the populations affected by the Disneyland-related measles outbreak are well below the necessary numbers to maintain herd immunity. Led by researchers at Boston Children’s Informatics Program, the project used disease data from the California Department of Public Health as well as current and historical data from the disease surveillance system known as HealthMap to estimate vaccination rates among the recent outbreak clusters. Researchers then used estimates of disease transmission among fully susceptible as well as immune populations to calculate their findings.

According to the Centers for Disease Control and Prevention, from January to March 20, 178 cases of measles have been reported in 17 states and Washington, D.C. The majority of the cases — 74 percent — were linked to the multistate outbreak traced back to Disneyland in Anaheim, California. CDC reports that the majority of those who have contracted the virus were not vaccinated. The JAMA Pediatrics report puts that point into even clearer focus, finding that inadequate vaccination rates were likely fueling the outbreak. (This may seem like a no-brainer, as public health officials made numerous pleas for people to get vaccinated in the wake of the outbreak. But in the world of public health, associations are rarely made without first seeing the science. This report is the first to positively link measles vaccination rates and the current outbreak.)

“Our data tell us a very straightforward story — that the way to stop this and future measles outbreaks is through vaccination,” said report co-author John Brownstein, a digital epidemiologist at Harvard and co-founder of HealthMap, in a news release. “The fundamental reason why we’re seeing the number of cases we are is inadequate vaccine coverage among the exposed.”

The report found that within measles outbreak clusters in California, Arizona and Illinois, the measles vaccination rate is likely between 50 percent and 86 percent. Both rates are well below what’s needed to protect the larger population. Because measles is so contagious, the report estimates that a vaccine rate of 96 percent to 99 percent is needed to preserve herd immunity and prevent future measles outbreaks. The report authors noted that their estimates only reflect vaccination rates among the exposed populations within each outbreak cluster and do not reflect nationwide rates or the overall rate for California. Report authors Brownstein, Maimuna Majumder, Emily Cohn, Sumiko Mekaru and Jane Huston write:

While data on MMR vaccination rates are available, coverage is often calculated at the state or county level and may not be granular enough to assess risk in an outbreak situation; this is especially the case for outbreaks originating at a tourist destination, where vaccination coverage among visitors is highly heterogeneous. Clearly, MMR vaccination rates in many of the communities that have been affected by this outbreak fall below the necessary threshold to sustain herd immunity, thus placing the greater population at risk as well.

In conjunction with the JAMA Pediatrics report, researchers at HealthMap also put together a dynamic model that shows how different vaccination rates affect the growth of a measles outbreak. The model shows that if a population is fully immunized against measles, one case of measles will result in only two additional cases within 70 days of the start of an outbreak. Using that same scenario and time period, the model found that a 90 percent vaccination rate would lead to 29 cases, an 80 percent vaccination rate would lead to just more than 200 cases, a 70 percent coverage rate would result in about 900 cases, and a 60 percent vaccination rate would lead to more than 2,800 cases.

Visit HealthMap to see the model for yourself. To request a copy of the JAMA Pediatrics report, click here.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.

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Yes I agree, the only way to reduce future outbreaks is through vaccination. The possible reason behind this sudden outbreak is clear: there has been an inadequate and insufficient use of vaccines. Does this mean more investment should go into improving the vaccination numbers?

By Tayla Rabie u1… (not verified) on 28 Mar 2015 #permalink

According to information found in the blog, measles and other diseases can be prevented from spreading through vaccinations. Coming from South Africa where in some areas there is simply no access to vaccinations or doctors, are there any other short term alternatives to the prevention of disease spreading? u15028047

By Dean Carlisle (not verified) on 29 Mar 2015 #permalink

The inadequate percentage of vaccinated individuals is both alarming and frightening. Is this blatant disregard for personal and general heath a sign of how narrow minded and short-sighted we have become as a society, or just another display of disturbing complacency in the general public?

By Hannah Nel (not verified) on 30 Mar 2015 #permalink

I do agree that the spreading of measles can be reduced by vaccination. Unfortunately not all children are vaccinated at an early age, therefor schools and the health department must work together to ensure that every child is vaccinated before a certain age.

By Michaela van Rooyen (not verified) on 30 Mar 2015 #permalink

Dean @ #2: Given that measles is a respiratory disease (airborne) and so very contagious, the only really effective ways of preventing the disease from spreading is having an immune population (either because they've been vaccinated or because they've survived a previous case of measles.)

You might (maybe) be able to quarantine a currently-healthy person away from the measles virus, but it would require total isolation. And given that the measles virus has been known to cause infection by hanging in the air for over two hours (in either a hallway or elevator, I'm not sure which) there really isn't anything anyone can do.

Which is why consistent vaccination is so important, all over the world.

By JustaTech (not verified) on 30 Mar 2015 #permalink

Because measles is so contagious, the report estimates that a vaccine rate of 96 percent to 99 percent is needed to preserve herd immunity and prevent future measles outbreaks. Kim

That is never going to happen, I mean even when it does like last year in the US when the CDC tell us they had the highest uptake of Pertussis vaccine ever, they had the highest outbreak of whooping cough ever too. To the man in the street that tells us the vaccine is a failure, it doesn't work. Herd immunity in Germany didn't help the boy that died either.

"The inadequate percentage of vaccinated individuals is both alarming and frightening. Is this blatant disregard for personal and general heath a sign of how narrow minded and short-sighted we have become as a society, or just another display of disturbing complacency in the general public?" Hannah

No, the public can see that the vaccine promise has failed, even when there is full coverage there are still outbreaks. You have to stop believing in vaccine mythology, it is the only thing keeping it alive apart from mass public funding

I do not think that the inadequate vaccination rates fueled the recent measles outbreak. Many people do not get vaccinated. Therefore the measles outbreak would have happened regardless of the inadequate vaccination rates. 15120521

By Anthony Micklesfield (not verified) on 31 Mar 2015 #permalink

Measels is a virus,can't the evolving of the virus be the conclusion for the outbreaks and not necesarilly inadequate vaccination? or maybe that the vaccination you got as a child wears off over time and now you are not so immune to it anymore?

Johnny @6: The pertussis (whooping cough) vaccine and outbreak don't have anything to do with measles.

Anthony@7: People not getting vaccinated is what "inadequate vaccination rates" means.

Kotze @8: The measles virus is pretty well conserved (it doesn't mutate very quickly) so that is probably not what is causing many outbreaks. It also seems unlikely when researchers look at the people who do get the measles during the recent outbreaks and the majority of people who are infected were not previously vaccinated.

By JustaTech (not verified) on 01 Apr 2015 #permalink

It's just so weird how we as humans only take necessary precautions if a disease is considered highly dangerous or fatal, for example when there was the swine flu outbreak everybody was urged to get vaccinated and it was done without hesitation. I feel no matter how small or big of an issue it may be, if you have an opportunity to avoid getting sick you should just get vaccinated to reduce the chances of contracting the disease.

By Thembekile Mkh… (not verified) on 01 Apr 2015 #permalink

Yes, I agree to the above blog article, that vaccination is the best way to implement prevention towards populations, infected by the measle disease. As future scientist and health practitioners, we have realised that we provide vast amount of awareness towards epidemic diseases like this, but for some odd reason communities are still not aware of the fact that the disease is present and even some have no access to medical assistance (e.g rural areas).

I think if one can tackle the rural infrastructures as a priority,educating/awareness towards epidemics like this, we would not have large stats based on the disease, larger vaccine dosages towards those communities would create less risk of such populations, making the disease less contagious to other individuals.

concluding that awareness plays one of many major roles in the implementation to fight of such diseases.

By Joshua Chris N… (not verified) on 01 Apr 2015 #permalink

Vaccination is the best prevention towards the measle epidermic. Early prevention is our greatest allied, against the disease. As well providing vast amount of awareness ,which will contribute towards individuals consisting of knowledge of such health threats. In that manner educating a population early enough of the disease can assist with prevention methodology against the disease.

By Joshua Ndoli( … (not verified) on 01 Apr 2015 #permalink

I personally do not believe that measles will ever be eradicated such in the way of small pox. Think a large deal of the difficulty with the vaccinations would be the poor immune response by the children resulting in a ineffective immunization. In poor countries you will also see the problem of malnutrition this certainly won't help the fight against measles.

By Charldon Viljo… (not verified) on 01 Apr 2015 #permalink

I think that the media is having a very big role when it comes to vaccinations. Many celebrities are openly stating that they refuse to have their own children vaccinated and ordinary citizens will then refuse to have their children vaccinated as they look up to their celebrities and just find the need to do whatever they do. Just because they are famous, people believe they know what is best. Not vaccinating children is extremely dangerous and could even prove fatal, not only with regards to measles but with regards to many other diseases as well.

Could vaccinations possibly be the reason many superbugs have not yet arisen?

By Nikita De Franca (not verified) on 02 Apr 2015 #permalink

While it is understandable that everyone has a right to refuse healthcare that they deem contradictory to their beliefs. When that belief affects the safety of the public that particular healthcare service should be mandatory. Vaccinations are seen as preventable treatments and it is my belief that they should be mandatory for all children. Failure to vaccinate your child not only impact that child but also the population negatively. Most of these diseases are airborne and easily transmittable for example measles. If a parent refuses to vaccinate their child against measles that child should not be allowed to interact with other children especially those that are immunocompromised.

By Dianne Palmer (not verified) on 02 Apr 2015 #permalink

I think today everyone believes that they're their own doctor. We all have access to the internet and so, so many people are choosing not to vaccinate. many perhaps believe they won't be affected. We should, in some way, try to increase awareness of the measles vaccination. Perhaps we could eradicate it entirely?

By Sachin Bhoora … (not verified) on 02 Apr 2015 #permalink

@16 Sachin Bhoora, yes I agree with your statement that, many individuals believe the mentality that they "will never contract the disease".

In a way this is why the measle stats are still so high, reason being they still being held by their stubbornness. They eventually do not realise what the consequences of their actions are by not taking the vaccine!

By Joshua Ndoli (… (not verified) on 02 Apr 2015 #permalink

I completely agree that vaccines are essential in the prevention of a disease especially in an outbreak. In South Africa the only required vaccine is for yellow fever. There needs to be more money put towards vaccines and they need to be of higher importance.

By Claire Gibbings (not verified) on 03 Apr 2015 #permalink

When looking at impoverished countries this simply highlights the need for improved health services. To improve vaccination rates by implementing the vaccines in schools or making the vaccines available in even the most remote or impoverished communities we would firstly have to improve health services to enable them to do this as it is currently a big challenge to maintain a high health standard in all communities.

By Maryke du plessis (not verified) on 04 Apr 2015 #permalink

I would also truly agree that the best way to prevent outbreaks of any sort of disease is to vaccinate people.

By Khanyisile Hlongwane (not verified) on 04 Apr 2015 #permalink

I believe that our government is trying when it comes to vaccination of children.Vaccination is the best way to prevent all outbreaks of disease.

By Khanyisile Hlongwane (not verified) on 05 Apr 2015 #permalink

The low rate of immunization is definitely alarming. It is clear that this is something that needs urgent attention. Unfortunately in countries such as South Africa not everybody is able to get vaccinated because of the fact that access is very limited and the amount of people unable to get vaccinated is just to large to accommodate each and every one of them. I suggest that the Deparment of Health and places like schools work together to try and accommodate as much children as possible and to ensure that vaccination takes place at a young age already. I also suggest that vaccination for measles is made compulsory to ensure that most of the people develops immunity against it.

@Johnny Comment #6

Yes it is clear that even if a vaccination rate of 96 to 99 percent is attained and herd immunity is preserved that there are still outbreaks. However, one must consider the fact that if vaccinations stopped completely or the vaccination rate dropped below 96 percent in these cases an outbreak would be far more devastating and the morbidity and most likely the mortality rate would be far higher. Vaccinations may not prevent an outbreak entirely or eradicate a disease completely but they certainly prevent a far worse outcome, would you not agree?

By Liam Waddicor … (not verified) on 05 Apr 2015 #permalink

I agree that vaccines are essential for prevention but whether it can stop out breaks is debatable.

The evolutionary process through which a new virus develop each year is natural selection. The current virus undergoes a mutation capable of surviving the current vaccine. This is probably the reason for cases still occurring in a fully vaccinated population. The new virus survives, comes along again the following year and a new vaccine is needed.

Though, vaccination is still the best possible way to contain and control out breaks.


By Liza Roos (not verified) on 05 Apr 2015 #permalink

In a country like South Africa we have a huge AIDS problem as well, especially in the rural areas. AIDS effects the immune system and makes the people more susceptible to other viruses such as measles. Therefor it is important that all the other people that comes in contact with someone who has AIDS should be vaccinated in order not to infect the HIV positive person and putting his life in danger. As a South African citizen I really have compassion towards people, especially children dying because of an illness that could be prevented. I strongly think that we as South Africans should stand together and come up with a plan to show our government that we want them to spend our tax money better. We want them to provide free vaccination for all people, no matter where they live or who they are.

By Marinda le Rou… (not verified) on 05 Apr 2015 #permalink

Vaccines play a big part in the prevention and control of diseases. Every person has the right to decide if they do or do not want healthcare, but if it is a decision that will have an effect on a community it must be enforced, this will then only be beneficial if you have the cooperation of the whole community.

By Ilze Dreyer (not verified) on 06 Apr 2015 #permalink

This must be enforced so that every person get the vaccines they need to help prevent outbreaks of diseases.

By Dileen Gouws (not verified) on 06 Apr 2015 #permalink

Vaccination against Measles must definitely be enforced however to enforce it would require money and action from the government. It would be a massive project if the government is too immunize all children and an incredibly expensive one too. We must consider the economical implications of such a project. But yes we need to get that 100% immunization.

By Surajlal, N (not verified) on 06 Apr 2015 #permalink

I believe it is extremely important that children must be vaccinated at an early stage.By avoiding vaccinations we endanger our lives as well as the lives of others.In some rural areas parents do not get their children vaccinated simply due to lack of knowledge.The government therefore needs to emphasize the importance of vaccinations.

By Payal Upadhyay (not verified) on 06 Apr 2015 #permalink

I think that the importance of vaccines is emphasized by the government we as people should start taking it more seriously as well. u15097367

By Khanyisile Hlongwane (not verified) on 06 Apr 2015 #permalink

A constant education campaign for vaccinations should be in place for new mothers-to-be. It needs to involve a broad spectrum of people where lack of knowledge occurs. Some people may have too little knowledge (illiterate and people living in remote areas) and other may interpret the internet knowledge out of context (the people believing that vaccinations result in autism). This is the reason why the Mail and Guardian stated that the measles outbreak in December 214 in South Africa "puts Ebola to shame" (u15021875)

Please ignore comment #18, I was incorrect when I mentioned about South African vaccinations. There are in fact 6 vaccinations that are compulsory for South Africans to take. As a South African traveller, to take the yellow fever vaccination is compulsory for certain countries. Should each country not have to adhere to vaccination regulations that ensures each country is vaccinated against the same five diseases?

By Claire Gibbing… (not verified) on 06 Apr 2015 #permalink

I believe that infants should be immunized against measles at birth and children in primary school should be immunized if they were not immunized at birth. But the most effective way is to immunize all infants at birth, thus not exposing anyone to measles. It is unnecessary for people more specifically children to die of something that can be prevented so easily. People, especially parents need to take immunizations more seriously.

By Michelle van Biljon (not verified) on 06 Apr 2015 #permalink

As important as immunization is,we should remember that immunization is not available for every sickness or disease.We should however receive the available immunization. (u15097367)

By Khanyisile Hlongwane (not verified) on 06 Apr 2015 #permalink

Those with proper knowledge of how detrimental such viruses could be , need to spread their knowledge even more to others who seem to be not aware of such . On the part of immunization everyone should be immunized and a platform such as media could be used to reach out to people as it seems some people do miss out on hearing or being aware of immunization . 13413890

By Lindokuhle N (not verified) on 07 Apr 2015 #permalink

I agree with Khanyisile Hlongwane that there is not necessarily vaccinations for every disease or virus, but there is to the topic that is being referred to - measles.

I agree with Khanyisile Hlongwane that there is not vaccines for all the diseases and viruses, but I believe in the specific case of measles, where there is a vaccine and has been for a long time, thus if people vaccinate their infants at birth, there would not be any problem.

I believe that to get vaccinated is very important and does help prevent the outbreaks and spreading of diseases, however i wonder why people on vaccinate themselves when they know there is a outbreak? I believe that all children should get vaccinated when they're born.

By Megan Soal (not verified) on 08 Apr 2015 #permalink

It seems like diseases that have been under control for a couple of years are resurfacing as of late. Are people still being informed and urged to vaccinate their kids at the prescribed times? Do the sister at the health clinics follow up on patients to see to it that mothers take their infants for vaccination? In South Africa we have a big influx of people from all over Africa- millions I think. These people come from poor countries and were not provided with adequate health services. Diseases that were eradicated for decades are brought into the country by the foreigners. Because these diseases were not common any more, some people felt vaccinations were unnecessary and with all the horror stories in the media stopped it completely. It seems we were wrong and a renewed effort should be made by government to get people to vaccinate their kids before we have an epidemic on our hands. 15026486

By Rens 15026486 (not verified) on 14 Apr 2015 #permalink